One-Pot Synthesis of Co-Doped VSe2 Nanosheets for Enhanced Hydrogen Evolution Reaction

We report a simple one-step hydrothermal method to fabricate cobalt (Co)-doped vanadium diselenide (VSe2) nanosheets on a carbon cloth for the hydrogen evolution reaction (HER) in acid solution. We find that the Co-doped VSe2 shows significantly enhanced catalytic activity compared with the pristine VSe2, including a low overpotential of 230 mV at 10 mA/cm2, a small Tafel slope of 63.4 mV/dec, and high stability. Our density functional theory calculations show that Co dopants dramatically reduce the Gibbs free energy for hydrogen adsorption (ΔGH), leading to improved catalytic activity for hydrogen evolution. Moreover, the Co doping promotes electron transfer and HER kinetics. Our results provide a valuable route to improve the catalytic performance of metal diselenide in HER.